OLMSTED, Ill. (AP) — Army Corps of Engineers officials are expected this fall to partially open new lock-and-dam system on the Ohio River between Illinois and Kentucky after 30 years of work.

Plans are that ships and barges be able to start using the Olmsted Locks and Dam in October, replacing a system dating to the 1920s.

The project to update the locks began in 1988, with an original completion date of 2013 and a price tag of $775 million. Project costs later increased to more than $3 billion.

Troubles with the existing Lock and Dam 52 downriver from Paducah, Kentucky, have led to some shipping companies avoiding the area near where the Ohio River flows into the Mississippi River, said Martin Hettel of American Commercial Barge Line.

"The sooner we can get Olmsted operational, the better the reliability is for moving the economic engine of this country, which is the in-land water system," Hettel said.

The project's cost grew because of a decision made in the late 1990s to use the "in-the-wet" construction process, said Mick Awbreyk, the Army Corps deputy chief for the Olmsted Division. The process involves lowering massive concrete building components into the Ohio River instead of that traditional cofferdam, which involves creating a dry space in the river to build.

A cofferdam system would've created dangerous water levels for barges along the waterway, said Waylon Humphrey, deputy chief of operations with the Corps' Louisville District.

Army Col. Antoinette Gant said the project will likely be fully operational by 2022.

The locks and dam consist of a network of channels for barge traffic to move through. The dam has 140 wickets, which are moveable pieces of steel that can be raised and lowered to hold or release water.